Turbomachine combustor having an externally fueled late lean injection (lli) system

ABSTRACT

A turbomachine combustor assembly includes a combustor including a combustor body extending from a head end to a second end through a combustion zone. At least one injector is configured and disposed to introduce a first combustible fluid into the combustion zone at the head end of the combustor body. At least one late lean injector (LLI) is configured and disposed to introduce a second combustible fluid downstream of the first combustible fluid. An external fluid delivery system is fluidically connected to the at least one LLI. The external fluid delivery system includes at least one combustible fluid delivery conduit that extends from a first end fluidically connected to the LLI to a second end external to the turbomachine combustor assembly. The second end is configured and disposed to deliver the second combustible mixture to the LLI.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to the art of turbomachines and, more particularly, to a turbomachine combustor having an externally fueled late lean injection (LLI) system.

Turbomachines include a compressor portion linked to a turbine portion through a common compressor/turbine shaft and a combustor assembly. An inlet airflow is passed through an air intake toward the compressor portion. In the compressor portion, the inlet airflow is compressed through a number of sequential stages toward the combustor assembly. In the combustor assembly, the compressed airflow mixes with a fuel to form a combustible mixture that is passed into a combustion chamber of a combustor. The combustible mixture is combusted in the combustion chamber to form hot gases. The hot gases are expanded through a number of turbine stages acting upon turbine buckets mounted on wheels to create work that is output, for example, to power a generator, a pump, or to provide power to a vehicle. Exhaust gases from the turbine portion are often times passed to a heat recovery steam generator which creates a steam flow that is passed to a steam turbine portion.

In general, the compressed air and fuel are introduced through a head end of the combustor via one or more fuel nozzles. The combustible mixture combusts in a combustion zone of the combustor and flows to the turbine portion through a transition piece. In some cases, an additional combustible fluid is introduced into the combustor downstream of the combustion zone. In other cases, the additional combustible fluid may be introduced into the transition piece. When combusted, the additional combustible fluid may consume un-combusted components of the combustible mixture to improve emissions from the turbomachine.

BRIEF DESCRIPTION OF THE INVENTION

According to one aspect of an exemplary embodiment, a turbomachine combustor assembly includes a combustor including a combustor body extending from a head end to a second end through a combustion zone. At least one injector is configured and disposed to introduce a first combustible fluid into the combustion zone at the head end of the combustor body. At least one late lean injector (LLI) is configured and disposed to introduce a second combustible fluid downstream of the first combustible fluid. An external fluid delivery system is fluidically connected to the at least one LLI. The external fluid delivery system includes at least one combustible fluid delivery conduit that extends from a first end fluidically connected to the LLI to a second end external to the turbomachine combustor assembly. The second end is configured and disposed to deliver the second combustible mixture to the LLI.

According to another aspect of the exemplary embodiment, a turbomachine system includes a compressor portion, a turbine portion operatively connected to the compressor portion, and a combustor assembly fluidically connected to the compressor portion and the turbine portion. The combustor assembly includes a combustor having a combustor body that extends from a head end to a second end through a combustion zone. At least one injector is configured and disposed to introduce a first combustible fluid into the combustion zone at the head end of the combustor body. At least one late lean injector (LLI) is configured and disposed to introduce a second combustible fluid downstream of the first combustible fluid. An external fluid delivery system is fluidically connected to the at least one LLI. The external fluid delivery system includes at least one combustible fluid delivery conduit that extends from a first end fluidically connected to the LLI to a second end external to the turbomachine combustor assembly. The second end is configured and disposed to deliver the second combustible mixture to the LLI.

According to yet another aspect of the exemplary embodiment, a turbomachine system includes a compressor portion, a turbine portion operatively connected to the compressor portion, a mechanical load drivingly connected to one of the compressor portion and the turbine portion, and an intake system fluidically connected to the compressor portion. The intake system is configured and disposed to condition fluid entering an inlet of the compressor portion. A combustor assembly is fluidically connected to the compressor portion and the turbine portion. The combustor assembly includes a combustor having a combustor body that extends from a head end to a second end through a combustion zone. At least one injector is configured and disposed to introduce a first combustible fluid into the combustion zone at the head end of the combustor body. At least one late lean injector (LLI) is configured and disposed to introduce a second combustible fluid downstream of the first combustible fluid. An external fluid delivery system is fluidically connected to the at least one LLI. The external fluid delivery system includes at least one combustible fluid delivery conduit that extends from a first end fluidically connected to the LLI to a second end external to the turbomachine combustor assembly. The second end is configured and disposed to deliver the second combustible mixture to the LLI.

These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF DRAWINGS

The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is schematic view of a turbomachine including a turbomachine combustor having an externally fueled late lean injection (LLI) system, in accordance with an exemplary embodiment;

FIG. 2 is a schematic side view of the turbomachine combustor of FIG. 1; and

FIG. 3 is an axial end view of a turbomachine combustor having an externally fueled late lean injection (LLI) system, in accordance with an aspect of the exemplary embodiment.

The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION OF THE INVENTION

A turbomachine system, in accordance with an exemplary embodiment, is illustrated at 2, in FIG. 1. Turbomachine system 2 includes a turbomachine 3 including a compressor portion 4 having a compressor casing 6 and a turbine portion 8 having a turbine casing 10. Compressor casing 6 and turbine casing 10 combine to form a housing 12 (FIG. 2). Compressor portion 4 is operatively connected to turbine portion 8 through a common compressor/turbine shaft 16. Turbomachine 3 also includes a combustor assembly 20 having one or more combustors 22 that fluidically connect compressor portion 4 and turbine portion 8. An intake system 24 is fluidically connected to an inlet 26 of compressor portion 4. Turbomachine 3 is also shown to be drivingly connected to a mechanical load 30. Mechanical load 30 may take on a variety of forms including pumping systems, energy generation systems as well as other types of mechanically driven systems. Turbomachine 3 also includes an external fluid delivery system 40 fluidically connected to combustor 22 as will be detailed more fully below.

In the exemplary embodiment shown, combustor 22 includes a combustor body 52 that extends from a head end 54 to a second end 56 through a combustion zone 58. A plurality of injectors 60 are arranged at head end 54. Injectors 60 receive fuel through a fuel delivery system 62 and air from a compressor discharge casing 63 formed internally in housing 12. The fuel and air mix to form a combustible mixture that is combusted in combustion zone 58 forming hot gases. The hot gases pass from combustor 22 through a transition piece 65 and expand through turbine portion 8. Transition piece 65 extends from a first end portion 68 to a second end portion 70 through an intermediate portion 72. First end portion 68 is mechanically linked to second end 56 of combustor 22 and second end portion 70 is fluidically connected to turbine portion 8.

In further accordance with the exemplary embodiment shown, combustor 22 includes a first late lean injector (LLI) 90, a second LLI 91 (FIG. 3) and a third LLI 92 (FIG. 3) mounted to combustor body 52. Of course, it should be understood that the number and location of LLI's may vary. LLIs 90-92 extend through combustor body 54 at a second combustion zone 93. Second combustion zone 93 is arranged downstream of combustion zone 58. Each LLI 90-92 includes a corresponding combustible fluid inlet 96-98 that receives a combustible fluid through external fluid delivery system 40. LLIs 90-92 introduce a second combustible mixture to combustor 22 that is combusted in second combustion zone 93. During full load operation, LLI's 90-92 reduce time spent by products of combustion at a final combustor exit temperature to reduce NOx. In part load operation, fuel to LLI's 90-92 may be substantially reduced or turned off completely. Under such conditions, additional fuel is provided at head end 54 to raise head end temperatures to oxidize CO. In this manner, the turbomachine maintains emissions compliance during both full and part load operation.

In still further accordance with the exemplary embodiment, external fluid delivery system 40 includes a combustible fluid delivery conduit 110 that extends from a first end 112 fluidically connected to combustible fluid inlet 96 to a second end 113 that is external to combustor 22. A fuel supply conduit 120 is fluidically connected to combustible fluid delivery conduit 110. More specifically, fuel supply conduit 120 extends from a first end portion 123 fluidically connected to second end 113 of combustible fluid delivery conduit 110 to a second end portion 124 through an intermediate portion 125. Second end portion 124 is fluidically connected to a fuel supply 126. Fuel supply 126 provides a source of fuel which may include combustible fluids, combustible gases, diluents and the like. A valve 130 is arranged along intermediate portion 125. Valve 130 controls passage of combustible fluid from fuel supply 126 to one or more of LLIs 90-92.

In yet still further accordance with the exemplary embodiment, external fluid delivery system 40 includes a non-combustible fluid supply conduit 140. Non-combustible fluid supply conduit 140 extends from a first end portion 143 to a second end portion 144 through an intermediate portion 145. First end portion 143 is fluidically connected to second end 113 of combustible fluid delivery conduit 110. Second end portion 144 of non-combustible fluid supply conduit 140 is fluidically connected to a compressor discharge casing 63 provided in housing 12. Compressor discharge casing 63 provides a supply of non-combustible fluid to LLIs 90-92. At this point it should be understood that the non-combustible fluid acts as an oxidizer to fuel and may include air, oxygen, diluents and the like. In addition, a valve 150 is arranged along intermediate portion 145 of non-combustible fluid supply conduit 140.

With this arrangement, fuel and air may be mixed externally of combustor 22 and be passed to LLIs 90-92 prior to introduction to combustor body 52. By mixing fuel and air external to combustor 22 pressure within combustible fluid delivery conduit 110 is less than compressor discharge air pressure at compressor discharge casing 63. As such, if a leak occurs, compressor discharge casing 63 will be isolated from fuel. That is, fuel will not pass into housing 12 through compressor discharge casing 63. In addition, the fuel/air mixture passing through combustible fluid delivery conduit 110 will have a pressure drop that substantially matches a total pressure drop within combustor body 52. As a result, the output velocity of the fuel/air mixture will be such that flame holding at LLIs 90-92 will be reduced. Also, as shown in FIG. 3, external fluid delivery system 40 may include a combustible fluid delivery conduit 160 that is fluidically connected to combustible fluid delivery conduit 110, as well as a second combustible fluid delivery conduit 163 and a third combustible fluid delivery conduit 165 that fluidically interconnect LLIs 90-92 through a junction member 168. Also, it should be understood that each LLI may include a dedicated non-combustible and combustible fluid supply.

While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. 

What is claimed is:
 1. A turbomachine combustor assembly comprising: a combustor including a combustor body extending from a head end to a second end through a combustion zone; at least one injector configured and disposed to introduce a first combustible fluid into the combustion zone at the head end of the combustor body; at least one late lean injector (LLI) configured and disposed to introduce a second combustible fluid downstream of the first combustible fluid; and an external fluid delivery system fluidically connected to the at least one LLI, the external fluid delivery system including at least one combustible fluid delivery conduit that extends from a first end fluidically connected to the LLI to a second end external to the turbomachine combustor assembly, the second end being configured and disposed to deliver the second combustible fluid to the LLI.
 2. The turbomachine combustor assembly according to claim 1, further comprising: a fuel supply conduit extending from a first end portion fluidically connected to the second end of the at least one combustible fluid delivery conduit to a second end portion through an intermediate portion, the second end portion being fluidically connected to an external supply of combustible fluid.
 3. The turbomachine combustor assembly according to claim 2, further comprising: a valve arranged in the intermediate portion of the fuel supply conduit.
 4. The turbomachine combustor assembly according to claim 2, further comprising: a non-combustible fluid supply conduit extending from a first end portion fluidically connected to the second end of the at least one combustible fluid delivery conduit to a second end portion through an intermediate portion, the second end portion being fluidically connected to a supply of non-combustible fluid.
 5. The turbomachine combustor assembly according to claim 4, further comprising: a valve arranged in the intermediate portion of the non-combustible fluid supply conduit.
 6. The turbomachine combustor assembly according to claim 4, wherein the second end portion of the non-combustible fluid supply conduit is fluidically connected to a compressor discharge casing.
 7. The turbomachine combustor assembly according to claim 1, wherein the at least one combustible fluid delivery conduit includes a first combustible fluid delivery conduit fluidically connected to a first LLI, a second combustible fluid delivery conduit fluidically connected to a second LLI, and a third combustible fluid delivery conduit fluidically connected to a third LLI, each of the first, second, and third combustible fluid delivery conduits being fluidically connected to a junction member.
 8. A turbomachine comprising: a compressor portion; a turbine portion operatively linked to the compressor portion; and a combustor assembly fluidically connected to the compressor portion and the turbine portion, the combustor assembly comprising: a combustor including a combustor body extending from a head end to a second end through a combustion zone; at least one injector configured and disposed to introduce a first combustible fluid into the combustion zone at the head end of the combustor body; at least one late lean injector (LLI) configured and disposed to introduce a second combustible fluid downstream of the first combustible fluid; and an external fluid delivery system fluidically connected to the at least one LLI, the external fluid delivery system including at least one combustible fluid delivery conduit that extends from a first end fluidically connected to the LLI to a second end external to the turbomachine combustor assembly, the second end being configured and disposed to deliver the second combustible fluid to the LLI.
 9. The turbomachine according to claim 8, further comprising: a fuel supply conduit extending from a first end portion fluidically connected to the second end of the at least one combustible fluid delivery conduit to a second end portion through an intermediate portion, the second end portion being fluidically connected to an external supply of combustible fluid.
 10. The turbomachine according to claim 9, further comprising: a valve arranged in the intermediate portion of the fuel supply conduit.
 11. The turbomachine according to claim 9, further comprising: a non-combustible fluid supply conduit extending from a first end portion fluidically connected to the second end of the at least one combustible fluid delivery conduit to a second end portion through an intermediate portion, the second end portion being fluidically connected to a supply of non-combustible fluid.
 12. The turbomachine according to claim 11, further comprising: a valve arranged in the intermediate portion of the non-combustible fluid supply conduit.
 13. The turbomachine according to claim 11, wherein the second end portion of the non-combustible fluid supply conduit is fluidically connected to a compressor discharge casing.
 14. The turbomachine according to claim 8, wherein the at least one combustible fluid delivery conduit includes a first combustible fluid delivery conduit fluidically connected to a first LLI, a second combustible fluid delivery conduit fluidically connected to a second LLI, and a third combustible fluid delivery conduit fluidically connected to a third LLI, each of the first, second, and third combustible fluid delivery conduits being fluidically connected to a junction member.
 15. A turbomachine system comprising: a compressor portion; a turbine portion operatively connected to the compressor portion; a mechanical load drivingly connected to one of the compressor portion and the turbine portion; an intake system fluidically connected to the compressor portion, the intake system being configured and disposed to condition fluid entering an inlet of the compressor portion; and a combustor assembly fluidically connected to the compressor portion and the turbine portion, the combustor assembly comprising: a combustor including a combustor body extending from a head end to a second end through a combustion zone; at least one injector configured an disposed to introduce a first combustible fluid into the combustion zone at the head end of the combustor body; at least one late lean injector (LLI) configured and disposed to introduce a second combustible fluid downstream of the first combustible fluid; and an external fluid delivery system fluidically connected to the at least one LLI, the external fluid delivery system including at least one combustible fluid delivery conduit that extends from a first end fluidically connected to the LLI to a second end external to the turbomachine combustor assembly, the second end being configured and disposed to deliver the second combustible fluid to the LLI.
 16. The turbomachine system to claim 15, further comprising: a fuel supply conduit extending from a first end portion fluidically connected to the second end of the at least one combustible fluid delivery conduit to a second end portion through an intermediate portion, the second end portion being fluidically connected to an external supply of combustible fluid.
 17. The turbomachine system to claim 16, further comprising: a valve arranged in the intermediate portion of the fuel supply conduit.
 18. The turbomachine system according to claim 15, further comprising: a non-combustible fluid supply conduit extending from a first end portion fluidically connected to the second end of the at least one combustible fluid delivery conduit to a second end portion through an intermediate portion, the second end portion being fluidically connected to a supply of non-combustible fluid.
 19. The turbomachine system according to claim 18, further comprising: a valve arranged in the intermediate portion of the non-combustible fluid supply conduit.
 20. The turbomachine system according to claim 15, wherein the at least one combustible fluid delivery conduit includes a first combustible fluid delivery conduit fluidically connected to a first LLI, a second combustible fluid delivery conduit fluidically connected to a second LLI, and a third combustible fluid delivery conduit fluidically connected to a third LLI, each of the first, second, and third combustible fluid delivery conduits being fluidically connected to a junction member. 